I have a 700GB mail datastore (consisting of millions of files) in a folder on my client. (basically just E:\MAILBOX... To move this across from client to server at Gb will take about 4 hours, I figure. Do I need to put the application to sleep during this 4 hour (or whatever) period? (or does FB handle this?).
If we go full first time, incremental forever, will I also have to pause or shutdown my application during the FB backup?
Pinned topic Question about locked/changing files
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Updated on 2010-12-07T15:30:41Z at 2010-12-07T15:30:41Z by MichaelSternberg
Re: Question about locked/changing files2010-11-19T16:13:11ZThis is the accepted answer. This is the accepted answer.No, you don't need to put application to sleep for 4 hours. FastBack performs so-called "hot" snapshot. Applications are instructed to stop for few moments at beginning of snapshot, so all writes, that belong to currently performed transactions, will be written to disk and volume, that is being backed up, will reach "consistent" state. After that snapshot will begin, while all applications, that perform reads or writes to that volume, will continue to work as usual. Snapshot, that will be created, will contain exact and consistent image of volume as it was at beginning of snapshot.
"Incremental forever" means that all snapshots will contain deltas from previous ones and, therefore, will be very fast and small. If you will perform shutdown of computer during snapshot - this snapshot will be aborted, but when computer will boot up again and next snapshot will run - it will back up only changes since previous successful snapshot, means it will be incremental.
And one additional point - FastBack is completely agnostic to number of files on backed up volume. It may a single file of 2TB or zillions of files, each one of 5KB, it doesn't matter to FastBack and does not affects any resources it takes.
Re: Question about locked/changing files2010-11-24T14:55:50ZThis is the accepted answer. This is the accepted answer.
- MichaelSternberg 2700024N9S
How does FB tell the applications to stop writing? (does the client tell the local OS automatically, or do I have to tell my mail server, ETC to pause via a script?).
Also, related to my previous question about the 4 hours, does TSM cache all the changes during that 4 hour time period so it gets a consistent backup? (there could be a ton of data changed over the 4 hour period)
Re: Question about locked/changing files2010-12-06T08:12:04ZThis is the accepted answer. This is the accepted answer.
- Derf 270001YFU4
FastBack provides consistency of snapshot using Copy-On-Write mechanism. Once snapshot is started each write, directed to volume that is being backed up, is intercepted, existing data from the disk is being backed up and intercepted write is allowed to proceed. Also, location of this write is remembered by FastBack in order to be backed up in next incremental snapshot.
Re: Question about locked/changing files2010-12-06T17:08:48ZThis is the accepted answer. This is the accepted answer.
- MichaelSternberg 2700024N9S
Ok, i'm dealing with a legacy app... so for a test of how long the pre-consistency period takes, would
it make sense to fire off an email from the pre-consistency, and another AFTER, so I can tell how long
my application needs to sit still? (use postie and send an email before/after via the script).
Also, would it make sense to NOT WORRY about it the first backup (as it is full backup FIRST time, then
"Incremental Forever" after that... and NOT use the first backup, but rely on the subsequent snapshots
(as they will take place much faster). That way I wouldn't even have to shut my mail application down AT
ALL for the first big/long backup... ??
Re: Question about locked/changing files2010-12-07T15:30:41ZThis is the accepted answer. This is the accepted answer.
- Derf 270001YFU4
You can rely on first full backup (if it was finished successfully) in the same way as you can rely on following incremental backups. But you will have to quiesce your mail application (to make it to flush all transactions to disk) for all backups, never mind it was the first full or following incrementals. Also, time of your application to be down (quiesced) doesn't differ for first full backup or for following incrementals. So the answer is no, there is no difference for you between first full backup and following incrementals apart time it takes to perform the backup. Of course the first full will take much more time, but your application will be able to work during it as usual - and the snapshot will be consistent and reflect state of volume as it was at backup start, or more exactly - at consistency point of time.